Safety device for machines such as punch presses and the like



April 1935- w. H. BRUSH El AL 1,997,101

SAFETY DEVICE FOR MACHINES SUCH AS PUNCH PRESSES AND THE LIKE Filed March 18, 1935 2 Sheets-Sheet 1 7 41mm INVENTORS April 1935- w. H. BRUSH ET AL 1,997,101

SAFETY DEVICE FOR MACHINES SUCH AS PUNCH PRESSES AND THE LIKE Filed March 18, 1935 2 Sheets-Sheet 2 B 4 Q y z/hATTo NEY- Patented Apr. 9, 1935 UNITED STATES SAFETY'DEVICE FOR MACHINES SUCH AS PUNCH PRESSES AND THE LIKE Walter H. Brush, Sea

Cliff, Long Island, and

Frank Slezak, Maspeth, Long Island, N. Y.

Application March 18,

. 18 Claims.

Our invention relates to safety devices for machines such as punch presses and the like, which are controlled by an operator and particularly to devices adapted toprevent careless or unrestricted operation of such machines.

Punch presses and machines of this general character are commonly provided with a source of power connected to the machine by a clutch or other means for starting and stopping the machine. The clutch is generally actuatedby some manipulative means such as a foot pedal under the control of the operator. the operator may intentionally or accidentally keep the pedal depressed so that the machine operates continuously while the work is inserted and removed from the machine. The operations are performed with such regularity that the operator tends to become careless and not infrequently' fails to remove his hand or a piece of work from the machinein time, and as a result the operator may be injured or the work damaged. The danger of such unrestricted operation of machines such as punch presses has been recognized and in many instances ordinances or laws have been passed requiring the provision in such machines of safety devices which necessitate operation of the foot. pedalor other manipulative means separately for each successive operation of the machine. 1

It has been proposed heretofore to eifectthis result by means of various electrical connections serving to operate the clutch between the driving element and the machine. Moreover, this result hasbeen attained heretofore by a clutch of been adapted for easy application to existing machines and have required expensive alterations in the structure of the machine or inthe mechanism for controlling the operation of the clutch,

In accordance with our invention, disadvantages and hazardspresented by the structures of the prior art are overcome and simple inexpensive means provided for preventing unrestricted or careless operation of the machine. In a preferred form of our invention the usual clutch between the driving element and the machine is employed and any suitable manipulative means, such as a foot pedal or hand lever, or in the event the machine is controlled by electricity, suitable push buttons or switches and solenoids 'or'magnets may be used. Inorder'to prevent continued operation of the machine, we provide a separable connection between the manipulative means and the clutch by means of which the separable members are automatically disconnected upon pre- In practice,

' special design. However, such devices have not 1933, Serial No. 661,500

determined movement of the machine and are only connected upon the release of the manipulative means. 7 The clutch is thereby released automatically so that movement of the machine is stopped upon completion of each operation 5 and will not again be initiated until the manipulative' means is released and again operated.

It is an object of our invention to prevent careless or unrestricted operation of machines such as punch presses and the like, and to provide an attachment adapted tobe applied to existing machines of various types and constructions for disconnecting the driving element from the ma,- chine upon the completion of a pre-determined operation of the machine.

Another object of our invention is to provide safety mechanism forrestricting the operation of a machine adapted to be applied as an attachment to existing machines with a minimum of expense and delay in applying the same.

A further object of our invention is to provide a safety device in the form of a unitary structure the elements of which are so constructed and assembled asto be capable of being applied as a unit directly to the frame of a machine or other support.

A further object is to provide a machine such as a punch press having a safety device adapted to cause the machine to stop upon the completion of each operation. 7

A further object of our invention is to provide a separable connection between the clutch and the manipulative means for operating the clutch.

A further object of our invention. is to provide automatic means for connecting and disconnecting the members of a separable connection between the clutch andmanipulative means for machines of the character described. 1

Another object of our invention is to provide latch mechanism adapted to be released upon the completion of a pre-determined operation of the machine, whereby further operation of the machine is prevented until the latch is again brought into operation by release of. the manipulative means. I

A further object of our invention is to provide safety mechanism which is simple and inexpensive to construct and operate and which comprises elements capable of withstanding continued and severe usage.

These and other objects and features of our invention will appear from the following description thereof in which reference is made to the accompanying figures of the drawings illusv trating a preferred embodiment of our invention. In the drawings: Fig. 1 is a front view of a punch press having a safety device embodying my invention applied thereto. V

Fig. 2 is a vertical sectional view through the form of safety device illustrated in Fig. 1 taken on the line 2-2 of Fig. 3 looking in the direction of the arrows.

Fig. 3 is a View of the safety device illustrated in Fig. 1 looking toward the left, with the cover of the device removed and parts broken away to show details of the construction.

Fig. 4 is aview partly in section indicated by the line 44 of Fig. 3 looking in the direction of the arrows.

In the form of our invention'illustrated in the figures of the drawings, a machine such .as a punch press is provided comprising a frame 2 and a reciprocating member or head 4 actuated by a rotatable shaft-:6 having a crank, eccentric or other means thereon for operating the connecting rod 8 for movingthe reciprocating .member up and down. The machine is powered by a driving element H! such as a pulley or motor; and is provided with clutching means l2 of usual or suitable construction adapted to connect and disconnect the driving element and the machine to operate the same. The clutching means is actuated ,byvpawl M or other device operable I by existing machines of standard construction .as

an attachment although the device maybe incorporated in such machines as an integral part thereof if desired. In order to enable the safety device to be quickly and easily applied to existing machines with a'minimum of expense and delay we prefer to employ elements and means so constructed and arranged that they may bemounted one single plate or other. supporting means forming a unitary structure that may be easily bolted or otherwise secured to astationary part of the machine such as the frame or bed.

. The safety device is preferably interposed be-; tween the manipulative means and the clutch and is so constructed and operated that the manipulative means is disconnected from the clutch upon the completion of an operation or upon predetermined movement of the reciprocatingmem her or other means driven by the machine as an incident to the operation thereof. For'this purpose we provide a separable connection between the manipulative means and the clutch comprising a member such as the rod 20 connected to the foot pedal or other manipulativemeans and a rod or member 22 connected to the pawl H or other element of the clutch I2.

"The safety device shown at 18 in Fig. 1 is located in'a suitable casing adapted to be attached as a unit to the frame of the machine or other support and serves automatically to connect and disconnect the numbers 20 and 22 connectedto the manipulative meansand clutch respectively. In the preferred form of the device illustrated a supporting plate24 may be provided element is longitudinally movable.

preferably secured directly to the frame 2 by 1 means of bolts 26 and provided with a removable cover 3| shown in dotted linesin Fig. 2. Bearings 32 and34 are rigidly secured to'the plate 24 by bolts 35 or may be formed integral with the plate if desired.

An actuating element 36 is slidably mounted in the bearings 30 and 32 and is connectedto the manipulative means by the rod or cable 20, one end of which is connected to an eye bolt 38 carried by the actuating element as shown, a spring 40 surrounds the element 36 and bears against the upper portion of the bearing 30 and against a shoulder 42 on the actuating element, serving to urge said element upward and to hold the member 20 and foot pedal [6 in raised position. Upward movement of the element 36 is limited by anysuitable means such as the collar 44 carried bysaid element and engaging the lower face of the bearing 30. V

The upper end of the actuating element 36 is slidable within the bearing 32 and is formed with a central opening within'which a clutch releasing A spring 48 shown in Fig. 1 urges the releasing element upward to separate said element from the actuating element whereby the clutch is disconnected from the manipulative means. Upward movement of the releasing element is limited by any suitable means such as a stop 50 carried thereby and adapted to engage a stop 52 mounted in the bearing 32 and projecting through a slot 54in the actuating element 36. The lower portion of the releasing element may be formed with-transe versely projecting lugs 56. As shown these lugs are formedon a pincarried by the lower portion of the releasing elementand held in flxed'position by the set screw 51 with the lugs extending laterally through the slots 58 in the actuating element. The'lugs 66 are formed with upwardly facing engaging surfaces 60 and lower cam sur faces 62. V

A latch carrying member 64 is cured to the actuating elementby screws 65 and is providedwith latches positioned to engage the lugs 56 on the releasing element. I These latches serve to connect the releasing element to the actuatingelement so that movement of the actuating element under the control of the manipulative means is transmitted to thereleasing,

element and'the clutch so that the clutch is operated to set the machine in motion. The latch carryingmember 84 is movable transversely of the actuating element-upon the studs 68 and 10 carried by saidelement and projecting throughopen-g ings in the latch carrying member. A spring shownhas' se- I2 surrounds the stud 68 and'urges the latch car rying member and the latches to the right, as shown in Fig. 3, so that the latches snap into connecting position above the projecting lugs 56 when the elements 36 and 46 are moved to their connecting positions, as shown in Figs. 2 and 3.

The upper surfaces ofl atches 66 are inclined and adapted to slide along the lower cam surfaces 62 of the lugs 56 upon upward movement of the 45 and to disconnect the members and 22 con-v nected to said elements so that the clutch I2 is disengaged, the safety device is provided with a tripping element 74 slidable in the bearing 34 on the plate as, The tripping element is shown as provided with a cam surface 16 movable into engagement with a projection 18 on the latch carrying member. Normally, the trip '14 is held in its lowered position by a spring 80 andthe cam surface It is located suihciently below the projection 18 to permit downward movement of the actuating element and the latch carrying member upon operation of the manipulative means without bringing the projection 18 into effective engagement with the cam surface'lfi. For this purpose, the trip may be provided with a dwell 8! above the cam surface against which the projection 78 normally bears.

Upward movement of the tripping element against the action of the spring 80 brings the cam surface 76 into engagement with the projec tion 18, shifting the latch carrying member and the latches 56 to the left, (see Fig. 3), so that the releasing member may be moved upwardly by the spring 48, disconnecting the member 22 from the member 20, causing disengagement of the clutch l2 so that the machine is stopped. Movement of the tripping element may be effected by any suitable means such as connections from the reciprocating member or the connecting rod 8 or other means driven by the machine as an incident to the operation thereof. As illustrated in the drawings, a cable 82 is provided which is connected at 84 to the connecting rod. The cable passes over the pulleys 86 and'BB mounted on the frame and the opposite end thereof is "connected to an eye bolt or other connecting means 90 on the tripping element 14 to move the trip upwardly upon completionof an operation or in response to a pre-deterhflned-movement of the reciprocating head and co-nnectingrod. The connectionbetween the reciprocating member and the tripping element preferably is such that the trip is not raised until the head 4 has descended to substantially the lower limit of its movement. Upon operation of the tripping element, the clutch and manipulative means are disconnected and the releasing element and lugs are raised above the latches 66 so that the connection remains broken until the manipulative means is released and the member 20 and actuating element 3'5 raised by the spring 44 to bring the latches 66 above the lugs 56 so that the latches may again snap into engaging position above the lugs 56 to connect the clutch and manipulative means preparatory to a succeeding operation.

With the construction described above, the machine is set intooperation by depressing the pedal it, which moves the member 20 and actuating element 36 downward. The latches 66 of the latching element 64, being in engagement with the lugs 56 on the releasing element, move the releasing element and the member 22 downward, actuatingthe pawl M to cause engagement of the clutch if! so as to connect the driving element In to the shaft 6, whereby the shaft is rotated and the reciprocating member 4 is moved downward to perform an operation. As the reciprocating member moves downward and approaches the lowerlimitof its movement, the cable 82 becomes taut, and as the reciprocating member continues to move, the cable pulls the tripping element" upward against the action of the spring 80, bring-. ing the cam surface 16 into engagement with the projection 18 on the latch carrying member. This member is then moved to the left, as shown in Fig. 3, against the action of the spring 12, mov ingthe latches out of engagement with the lugs 58011 the releasing element. The spring. 48 then moves the member 22 and the releasing element upward so that subsequent movement of the reciprocating head into position to permit the tripping element to move downward and allow the latch carrying member to again move to theright will not result in connecting the releasing element to the actuating element. It is'then necessary to release the manipulative means before the ma chine can be further operated. Upon release of the manipulative means, the actuating element is raised by the spring 40 and the upper faces of the latches 56 engage the lower cam surfaces lative means is connected to the member 22 con- 7 nected to the latch. The device is then in position to permit another operation of the machine.

While our invention'has been shown and described as appliedto punch presses, and a premechanism for connecting the driving element to the machine, and manipulative means for actuating said mechanism, a safety device comprising means adapted to be interposed between the manipulative means and said mechanism to connect the same, and. an element actuated by the machine as an incident to its operation serving to disconnect said manipulative means from said mechanism to cause stopping of the machine.

2. In a. machine having a driving element, a v

clutch for connecting the driving element to the machine, and manipulative means for actuating said clutch, a safety device comprising a latch interposed-between said'manipulative means and said clutch serving to connect the same, and means actuated by the machine as an incident to its operation to release said latch and disconnect said manipulative means from the clutch to cause stopping of the machine.

3. In a machine such as a punch press, having.

a driving element, a clutch and manipulative means for actuating said clutch to connect said driving element to-the machine to operate the same, a safety device comprising .a latch interposed between said clutch and said manipulative means for connecting the same, a trippingv element movable to release said latch and disconnect said. manipulative means from said clutch, and means operable by the machine upon a pre-determined movement thereof for actuating said tripping element to disconnect said clutch and manipulative means and cause said machine to stop.

4. In a punch press or the like, having a driv ing element, clutching means for connecting the driving element to the machine'to operate the ing separable members for connecting said mainipulative means to the clutch and means for connectingand disconnecting said members including an actuating element, a releasing elenecting said manipulative means to said clutch,

positioned adjacent each other,

ment, a latch carried by one of said, elements adapted to engage the other element, and means actuated by the machine as an incident to its operation serving to disengage'said latch from said other element. I

'6.'In a machine having a clutch movable to effect operation of the machine and manipulative means for actuating saidv clutch, a safety device comprising separable members for conmeans operable upon release of said manipulative means, for connecting said separable members, and means movable to disconnect said separable members upon completion of a pre-determined operation of said machine. s

'7. In a machine such as a punch press or the i like having a clutch, manipulative means for'the clutch, and a connection between'the clutch and manipulativemeans, a safety device comprising an element connected to the clutch and forming a part of the connection" between the clutch and manipulative means, a second element con nected to the manipulative means and forming a part of the connection between the clutch'and' manipulative means, a latch carried by one element and engaging the other element,.means for urging said latch into engagement with said other elements whereby movement'of the members into 'a pre-determined position automatically connects the same, a tripping element actuated by the machine movable todisengage' said latch from said other elements, and means for urging said elements apart whereby release of said latch causes said elements to be separated.

8. In a power press comprising aclutch and manipulative means therefor, a safety device for connecting said manipulative means to. said clutch comprising relatively movable elements connecting means carried by one element and adapted to engage the other element," means for resiliently .urging said connecting means into engagement with said other element and means actuated by the machine for moving saidconnecting means out of engagementwith said other element.

9. In a power press a clutch and manipulative means therefor, an element connected to said manipulativemeans, a second element, connected to said clutch, a latch carried byone of said elements and urged into engagement with the other element to connect said manipulative means to said'clutch and a tripping element actuated by the 'machine to disengage the latch from the other element.

10. In a punch press or other machine having.

a clutch and manipulative means therefor, a safety device comprising members connected to said manipulative means and clutch respectively,

a. unitary structure comprising a plate adapted to be secured to the frame of the machine and having elements supported thereon for connecting and disconnecting. said members and means actuated by the machine as an incidentto its operation to effect movement of said elements to operate the same, manipulative means for actuating said mechanism, means interposed between said manipulative means and said mechanism serving to connect the.same,;and a tripping element actuated by the machine upon a meet said manipulative means from said mechanism to cause stopping of the machine.

,12. A device for controlling the operation of a machinesuch as a punch press or the like com prising a driving element, clutch mechanism for connecting thedriving element to the machine to operate the same, rnanipulativemeans for actuating said'clutch mechanism, a latch interposed between the said manipulative means and said clutch mechanism serving to connect the same, and a tripping element actuated by the machine upon a pr'e-determined performance thereof to releasesaid latch and disconnect the manipulative means from said clutch mechanism tocause stoppingof the machine.

13. A device for controlling the operation of a machine such as a punch press or the like comprising a: driving element,-clutch mechanismfor connecting the driving element to the machine 'pre-determined performanceithereof to. discOntooperate the same, manipulative means for V actuating said clutch mechanism, a separable connection between said manipulative means and the clutch mechanism, va latch for connecting the separable members of said connection, and a tripping element actuated by the machine upon theperformanoe of a single operation'thereof to release said latch whereby said members are separated and said manipulative means is disconnected from said clutch mechanism. 7

14. A device for controlling the operation of a machine such as a punch press or the like comprising a driving element, clutch mechanism for connecting the driving element to themachine to operate the same, manipulative means for actu ating said clutch mechanism, a separable connection between said manipulative means and the clutch mechanism, a latch for connecting the separable members of said connection serving to connect said members upon release of saidma nipulative means, and a tripping element actuated by the machine upon the performance of a single operation thereof to release said latch whereby said members are separated and said manipulative means is disconnected from said clutch mechanism. V t V 15. In combination with a punch press or, the like, a reciprocating member, a driving element, mechanism for connecting the driving element to the reciprocating element, manipulative means for actuating said mechanism, means interposed 5 between said manipulative means and said mech-' anism serving to connect the. same, a tripping 'elesaid latch out of engagement with saidreleasing.

like, a reciprocating member, a driving element, clutch mechanism for connecting the driving element to the reciprocating element, manipulative means for actuating said clutch mechanism, a latch interposed between said manipulative means and said clutch mechanism serving to connect the same, a tripping element for said latch and means actuated by said reciprocating member to operate said tripping element and release said latch to disconnect themanipulative means from the clutch mechanism.

17. In a machine such as a punch press, a reciprocating member, a driving element, a clutch for connecting said driving element to said reciprocating member, manipulative means for actuating said clutch and means-for connecting and disconnecting said manipulative means and clutch to prevent unrestricted operation of said reciprocating member comprising separable members connected to said manipulative means and said clutch respectively, an actuating element connected to one of said separable members, a releasing element connected to the other of said separable members and positioned adjacent said actuating element, a latch carried by said actuating element and movable into engagement with the releasing element to connect said members and a tripping element connected to the reciprocating member and movable upon the completion of a pre-determined operation thereof to move 18. In a machine such as a punch press, a reciprocating member, a driving element, a clutch for connecting said driving element to said reciprocating member, manipulative means for actuating said clutch and means for connecting and disconnecting said manipulative means and clutch to prevent continued operation of said reciprocating member, comprising separable members connected to said manipulative means and said clutch respectively, an actuating element connected to one of said separable members, a releasing element connected to the other of said separable members and positioned adjacent the actuating element, a latch carried by said actuating element and movable relative thereto-into engagement with the releasing element to connect said elements, a spring for urging said latch into engagement with said releasing element and a tripping element connected tothe reciprocating member and movable upon the completion of a pre-determined operation thereof to remove said latch from engagement with said releasing element against the action of said spring to disconnect said elements and cause stopping of the machine.

WALTER H. BRUSH. FRANK SLEZAK. 

